A 6061 Al coating for AZ31 Mg alloy was prepared by multi-pass friction stir welding (FSW) with different travel speeds. The microstructure, mechanical properties of the interfacial region and the corrosion behavior of the coating were investigated systematically. The results indicate that the interfacial intermetallic compounds formed in the stir zone (SZ) consist of mainly Al12Mg17 and Al3Mg2. The intermetallic compounds in the SZ are significantly increased when the travel speed is increased from 30 mm/min to 60 mm/min. Microhardness measurements and results of shear-tensile tests show that the mechanical properties are influenced by the intermetallic compounds formed in the SZ during FSW. Corrosion tests indicate that the 6061 Al coating can significantly improve the corrosion resistance of AZ31 plate. The 6061 Al coating obtained with a travel speed of 30 mm/min has a maximum corrosion potential Ecorr of -0.503 VVSE.

The hot deformation and dynamic recrystallization behavior of the dual-phase Mg-9Li-3Al-2Sr-2Y alloy had been investigated using a compression test. The typical dual-phase structure was observed, and average of grain size of as-homogenized alloy is about 110 µm. It mainly contains β-Li, α-Mg, Al₄Sr and Al₂Y phases. The dynamic recrystallization (DRX) kinetic was established based on an Avrami type equation. The onset of the DRX process occurred before the peak of the stress–strain flow curves. It shows that the DRX volume fraction increases with increasing deformation temperature or decreasing strain rate. The microstructure evolution during the hot compression at various temperatures and strain rates had been investigated. The DRX grain size became larger with the increasing testing temperature or decreasing strain rate because the higher temperature or lower strain rate can improve the migration of DRX grain boundaries. The fully recrystallized microstructure can be achieved in a small strain due to the dispersed island-shape α-Mg phases, continuous the Al₄Sr phases and spheroidal Al₂Y particles, which can accelerate the nucleation. The continuous Al₄Sr phases along the grain boundaries are very helpful for enhancing the corrosion resistance of the duplex structured Mg-Li alloy, which can prevent the pitting corrosion and filiform corrosion.

The effect of Ca addition on the microstructure, mechanical properties, and corrosion behaviors of the extruded Mg–7Li–3Al alloys was investigated. The results showed that the extruded Mg–7Li–3Al–xCa alloys consisted of α-Mg (hcp) + β-Li (bcc) matrix phases and Al₂Ca. With increasing Ca content, the amount and morphology of the Al₂Ca phase changed significantly. The grains of the extruded Mg–7Li–3Al–xCa alloys were refined by dynamic recrystallization during the extrusion process. The tensile tests results indicated that the extruded Mg–7Li–3Al–0.4Ca alloy exhibited favorable comprehensive mechanical properties; its ultimate tensile strength was 286 MPa, the yield strength was 249 MPa, and the elongation was 18.7%. The corrosion results showed that this alloy with 0.4 wt.% Ca addition exhibited superior corrosion resistance, with a corrosion potential E_corr of −1.48742 V_VSE, attributed to the formation of protective Al₂Ca phases.